A glass which contains (1) an alkaline earth oxide that is BaO, SrO, or mures thereof, (2) Al.sub.2 O.sub.3, and (3) SiO.sub.2. The glass is useful as a sintering aid in the preparation of monoclinic BaO.Al.sub.2 O.sub.3.2SiO.sub.2 or monoclinic SrO.Al.sub.2 O.sub.3.2SiO.sub.2 ceramic

A Si.sub.3 N.sub.4 reinforced aluminosilicate ceramic composite made ofA. from about 5 to about 40 weight percent of Si.sub.3 N.sub.4 reinforcem material;B. from about 15 to about 35 weight percent of the recrystalization products formed from a molten glass composed of(1) from about 8 to ab

A ceramic electromagnetic window made of Si.sub.3 N.sub.4 particles which are bonded together by a metal phosphate binder that is an AlPO.sub.4 binder, a ZrP.sub.2 O.sub.7 binder, or mixtures thereof, wherein the Si.sub.3 N.sub.4 particles comprise from 55 to 85 volume percent of the

A Si.sub.3 N.sub.4 reinforced aluminosilicate ceramic composite made ofA. from about 5 to about 40 weight percent of Si.sub.3 N.sub.4 reinforcem material;B. from about 15 to about 35 weight percent of the recrystalization products formed from a molten glass composed of(1) from about 8 to ab

A Si.sub.3 N.sub.4 reinforced aluminosilicate ceramic composite made ofA. from about 5 to about 40 weight percent of Si.sub.3 N.sub.4 reinforcem material;B. from about 15 to about 35 weight percent of the recrystalization products formed from a molten glass composed of(1) from about 8 to ab

There is disclosed herein an invention for beneficiation of powered material having superconducting characteristics and processes for carrying it out. The invention involves introducing powdered superconducting material into the vertical field of a magnet wherein particles thereof are

A process for preparing monoclinic celsian from AlF.sub.3, Al.sub.2 O.sub.3, BaCO.sub.3, and fused SiO.sub.2 powders by heating an intimate mixture of the powders (1) at from about 700.degree. to 900.degree. C. to form topaz and then (2) at a temperature as low as 900.degree. C. to p

A process for preparing monoclinic celsian from topaz and BaCO.sub.3, pows by heating an intimate mixture of the powders at a temperature of from 900.degree. C. to less than 1590.degree. C. in an atmosphere of the gases generated by the monoclinic celsian formation reaction itself.

A process in which (1) AlF.sub.3 and SiO.sub.2 or AlF.sub.3, SiO.sub.2, and Al.sub.2 O.sub.3 powders are formed into a green body of a desired shape and size; (2) the green body is heated at 700.degree. C. to 950.degree. C. in an anhydrous SiF.sub.4 atmosphere to form barlike topaz cryst

A process for preparing mullite, 3Al.sub.2 O.sub.3.2SiO.sub.2, whiskers by(1) forming an intimate, anhydrous mixture of AlF.sub.3 and SiO.sub.2 powders in about a 12:13 molar ratio;(2) heating the mixture in an anhydrous, SiF.sub.4 atmosphere at about 700.degree. C. to about 950.degree. C. t